Waist-Hip Ratio Better for Gauging

In a new study researchers from the David Geffen School of Medicine at University of California, Los Angeles, (UCLA) found that the waist-to-hip circumference ratio was a better yardstick for assessing obesity in high-functioning adults between the ages of 70 and 80, presumably because the physical changes that are part of the aging process alter the body proportions on which BMI is based.

Using data from the MacArthur Successful Aging Study — a longitudinal study of high-functioning men and women between the ages of 70 and 79 — researchers examined all-cause mortality risk over 12 years by BMI, waist circumference and waist-hip ratio. They adjusted for gender, race, baseline age and smoking status. The average age of participants was 74.

Obesity is often associated with premature mortality because it leads to an increased risk of diabetes, heart attack, stroke and other major health problems, the study authors say.

The researchers found no association between all-cause mortality and BMI or waist circumference; the link was only with waist-hip ratio. In women, each 0.1 increase in the waist-hip ratio was associated with a 28 percent relative increase in mortality rate (the number of deaths per 100 older adults per year) in the group sampled. If hip size is 40 inches, an increase in waist size from 32 to 36 inches signaled a 28 percent relative death-rate increase.

The relationship was not graded in men. Instead there was a threshold effect: The rate of dying was 75 percent higher in men with a waist-hip ratio greater than 1.0 — that is, men whose waists were larger than their hips — relative to those with a ratio of 1.0 or lower. There was no such relationship with either waist size or BMI.